Multiple Windows in Windows Universal Apps

Although I was very relieved to find Windows Store Apps (previously Metro Apps and soon to be Universal apps) to be much nicer on Windows 10 compared to Windows 8, simply because they opened up in a separate windows instead of taking up the whole screen, there is one, very common GUI paradigm that I missed. That was, the concept of multiple windows per application.

Looking at the Store Apps that Microsoft itself has provided, multiple windows have been very much deemphasised. For example, in the Mail application, I have been unable to find a way to open up individual messages in a separate window. In Word Mobile, the application even explicitly saves and closes the current document when you choose a new one from the “open” menu.

Microsoft actually has developer guidelines regarding applications with multiple windows. Although they clearly mention that it is possible to create an application with multiple windows, and give you directions on how you should implement it, they also make it clear that you should be careful and deliberate about it.

  • Design new windows that allow users to accomplish tasks entirely within the window.
  • Don’t automatically open a new window when a user navigates to a different part of the app. The user should always initiate the opening of a new window.
  • Don’t require the user to open a new window to complete the main purpose of the app.

You can see an example of multiple windows in the Windows 10 calendar app when you view the details of an appointment. Note that opening an appointment in a separate window is a two-step process. You first have to view the details in the same window, and from there, you click the button on the upper right to open a new window.


Because multiple windows has become such a common GUI concept on PCs, I expect many users to be confused or at the least irritated at this change. On the other hand, from a developer point of view, it is totally understandable that this makes it easier to create a single application spanning mobile and PCs.

Hopefully, Microsoft will think up new ways to bring the benefits of multiple windows to Windows Store apps, because simply, I think this UI policy is too restricting and unfamiliar except for anything but the simplest of apps. The hope is that Microsoft is seriously contemplating converting the current MS-Office apps to Windows Store apps, instead of providing separate versions (currently Word, Excel, PowerPoint Mobile for Windows Store, and Word, Excel, PowerPoint 2013 for traditional desktops). That would be something.